README: fix pkg.go.dev badge link to point to memcache package

README.md

diff --git a/README.md b/README.md
index 714913c..90f66ab 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 ## About
 
-[![Go Reference](https://pkg.go.dev/badge/github.com/bradfitz/gomemcache.svg)](https://pkg.go.dev/github.com/bradfitz/gomemcache)
+[![Go Reference](https://pkg.go.dev/badge/github.com/bradfitz/gomemcache/memcache.svg)](https://pkg.go.dev/github.com/bradfitz/gomemcache/memcache)
 
 This is a memcache client library for the Go programming language
 (http://golang.org/).